In September 1968, the FDP of AGARD held a specialists' meeting in Paris on transonic aerodynamics, in recognition of the fact that the absence of adequate theoretical methods and wind-tunnels of high enough Reynolds number had already led to costly shortcomings in the transonic performance of certain combat and transport aircraft. Since projected aerospace systems, military, civil and space-oriented, would involve flight at Reynolds number of up to 100 million, the FDP undertook an examination of the requirements of NATO nations for wind tunnel facilities for testing large models at high Reynolds numbers.